MOEPHOLOGY. 



The tube and the basal part of the hood are of the same texture, and are more delicate 

 than the lip which in turn is thinner than the hood proper with which the beak, when 



The only exception to this is in the Anodont-e, where hood and lip 



uniform 



tions 



nresent, is unitorm. m« ^u.j «~ wt — - — 



aveof the same consistence as the tube. In the corolla as a whole there are all grada 



from the greatest delicacy (P. Kingii, gracilis) to a sub-coriaceous texture (P. tricho- 

 „M««) The nerves of the tube are parallel and pass into both lip and hood. In parti- 

 Liar species the nervation is highly constant, and in the lip may consist of one central 



nervules for each lobe, of one central main nerve in the midlobe, 

 and "threTmain "nerves in each lateral lobe, or of three main nerves in every lobe. The 



nerve wi 



th lateral 



wim branch to both sides ; the lateral main nerves, more especially of the 



inidbbVbranch to the outside only as a rule, though sometimes all three nerves in each 



ral main 



cf the three lobes branch in both directions. The secondary nervules always anastomose 

 though often not very visibly; sometimes, however, the anastomosis gives a character- 

 istic °areolate appearance to the lip (P. Scullyma). The nerve in the tube that corre- 

 sponds to the insertion of the posterior stamen on each side does not pass vertically 

 upwards into the hood, but arches forward and ends in the margin at the point which 

 indicates the junction of the base with the hood proper. As a rule, this nerve simply 

 disappears in the thickened margin, but sometimes (P. siphonantha, odontophora) it is 

 prolonged as the median nerve of a distinct tooth ; at other times (P. longiflora, furfu- 



/ °it is lost at the base of a distinct sinuation. This nerve gives off from its upper 

 convex aspect a series of parallel branches that form, along with the prolonged nerves 

 of the tube posterior to the two arching nerves, the nerve system of the hood proper 



and, if it be present, of the beak also. 



Steven Ion"- aso observed that in many species with a spicate inflorescence the 



o ~© 



whole corolla is obliquely twisted, so that a spiral arrangement of the flowers is the 

 result, and that in almost all the species known to him the lip is oblique. Maximowicz, 

 too, has observed in living specimens that in some species the whole corolla, but more 

 especially the hood, is twisted dextrorsely (with the sun), the lip at the same time 

 being oblique, but without noting whether the npper surface of the lip looks towards 

 or is averted from the sun. 1 Nothing can be said definitely of obliquity of lip in dried 

 specimens, but as regards the hood the twisting is very evident, even in the herbarium. 

 Sometimes it involves both tube and hood (P. macrantha)\ at other times it is confined 

 to the hood (P. exceha). The significance of this phenomenon is worthy of study in the 

 field ; the morphological result and the arrangements by which it is effected are capable 

 of interpretation, in the case of the LONGIROSTRES at all events, and if a sufficient 

 number of flowers be examined, even in the herbarium. Whatever the arrangement may 

 he, the result is in every case the same — the removal of the apex of the beak, and along 

 with that the stigma, from the lip, which is presumably the platform inviting insect visit, 

 ants to the flower. One arrangement which effects the result is met with in the flexuose- 

 beaked OitTHORRHYNCHiE (P. pectinata). Here the flower does not open till the beak is 

 fully elongated. The apex of the beak is at the margin of the midlobe of the lip; the 

 terminal convoluted portion of the beak is lodged in this lobe, the portion behind being 

 straight. While the flexuous portion is being developed in this confined space, it becomes 

 as a matter of accommodation, twisted on its own long axis, and this twist becoming 

 permanently impressed on the beak, causes its apex, and along with it the stigma, to be 

 averted from the lip (Plate 23, f. 12), instead of turned towards it (Plate 23, f. 1) 

 when the flower opens. But this is not all. The elongating beak tends to push the 







1 Maximowicz, Met. Biol, xii, 77 5. 





